Conveyer



May 17, 1932- w. B'COIOLEYV CONVEYER Filed May 22, 1929 5 Sheets$heet lattozmq Patented May 17, 1932 UNITED STATES PATENT OFFICE WILLIAM B.COOLEY, F MILWAUKEE, WISCONSIN, ASSIGNOR- TO HEVI DUTY ELECTRIC COMPANY,OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN CONVEYER Applicationfiled May 22,

My invention relates'broadly to furnaces and more particularly to afurnace of the belt conveyer type.

v One of the objects of my invention is to provide a construction offurnace employing a belt type of conveyer for the heat treatment ofsmall parts without containers therefor and without loss of heat fromthe conveyer. 7 Another object of my invention is'to provide means forcontrolling the movement of the conveyer in a heat treatment furnacewhere special provision is made to prevent distortion and abrasive wearof the conveyer belt.

Still another object of my invention is to provide a construction ofconveyer type furnace where roller members are provided to relieve thestrain upon the conveyer belt as a the conveyer moves material to beheat treated through the furnace.

A further object of my invention is to provide a construction ofmounting for the conveyer belt in a heat treatment furnace whereinboththe upper and lower moving portions I of the belt may be supported torelieve the strain on the belt and prevent distortion of the conveyerbelt under conditions of continued use.

A still further object of my invention is to provide a: system fordriving an endless belt conveyer which is disposed wholly within a heattreatment furnace, with means for moving the belt through the furnacewith minimum loss of heat while preserving the belt conveyer againststrain under conditions of load to which the belt conveyer may besubjected.

Other and further objects of my invention reside in the construction ofconveyer belt for heat treatment furnaces as set forth more fully in thespecification hereinafter followingby reference to the accompanyingdrawings, in which:

Figure 1 is a side elevation of a heat treatment furnace showing thedrive system for the rollers which operate simultaneously with themovement of the belt conveyer; Fig. 2 is a fragmentary plan view of thedrive system for the rollers and belt conveyer in the n heat treatmentfurnace of my invention; Fig.

1929. Serial No. 365,122.

o is an end view of the heat treatment fur-, nace to which the conveyersystem of my invention is applied; Fig. 4; is a lateral crosssectionalview taken through the furnace structure on line l4= of Fig. 5; and Fig.5 is a longitudinal sectional view taken through the heat treatmentfurnace and showing the belt conveyer system diagrammatically incross-section.

Here-tofore in the art it has been customary to employ so called rollerbottom furnaces as a conveyer where the driven rollers receive pans ortrays containing small parts for heat treatment within a furnacestructure. Llnk or woven belts have been used for the same purpose whereparts of the charge, unless in pans or trays, would fall through themesh or weave of the belt. The lighter weight belt preferably used in myinvention,

may be made with a mesh sufiiciently fine as to prevent small pieces,such as lock-washers, set screws, etc, falling through the belt. The useof such containers causes unnecessary loss of heatdue to the necessityof heating the trays which do not form part of the furnace product.WVhere conveyers of the link or woven belt type, carrying the parts tobe treated, have been used in heat treatment furnaces, the tensionapplied to the belt, in order to render the belt effective as aconveyer,

has resulted in distortion and also abrasive wear on the underside ofthe belt where it slides over the furnace bottom. This causesunnecessarily frequent replacement of the belt.

In the conveyer system of my invention I overcome the disadvantagesheretofore eX- perienced in the art, by providing a continuous belt orconveyer of less weight than heretofore required, and I support the beltat a plurality of intervals between the driving drums over which thebelt passes by means of rollers which are simultaneously driven, themovement of the rollers being coordinated with the movement of theconveyer belt for the passage of material under heat treat ment throughthe furnace. I also provide driven means which serve to support thelower portion of the conveyer during the return cycle of the conveyer tofurther relieve the strain upon the conveyer and improve the operationthereof.

Referring to the drawings in more detail, reference character 1designates a typical heat treatment chamber formed by walls 2 which maybe of fire brick which is surrounded at the top, bottom and sides byheat insulating material 3, which is in turn enclosed by a steel shell 4having cast iron heads 5 closing opposite ends of the furnace. At thefront end of the furnace I provide a heat insulated door 6 slidablyarranged to be moved by suitable means to different vertical positionsto allow insertion into the furnace of various sized articles to be heattreated and to permit the heat treatment chamber to be closed wheneverrequired. At the opposite end of the furnace, I provide a rear door 7which may be heated by suitable means, such as electrical elementsrepresented at 8, this door 7 being intended for any emergency use. Thefurnace chamber may be heated by any suitable means, and for the purposeof explaining my invention, I have shown the furnace electrically heatedby heating elements 9 diagrammatically illustrated as mounted in thetop, sides and bottom of the furnace chamber. In mounting the heatingelements on the top and side walls of the furnace chamber, I prefer toemploy the type of heater element mounting set forth in copendingapplication Ser. No. 279,810, filed May 22, 1929, by Edwin L. Smalley.

I provide a multiplicity of power driven rollers 10 which have shaftsextending laterally through the furnace chamber and through the wallsthereof in the same horizontal plane, which rollers serve to support asuitable endless belt 11 which may be of woven or link construction. Thebelt 11 passes over the driving drums or rotary cylindrical members 12and 12a and over the several rollers 10 and is driven and supported bythe coordinated operation of the driving drums and rollers. The belt 11is relatively slack and when loaded the belt forms into catenariesbetween the rollers. These catenaries form undulations so that any onetransverse section of the belt proceeds through the furnace in wave-likeprojection. This wave-like motion causes a slight tumbling action tosmall parts of the charge on the belt. This action is suificient toprevent adjacent parts of the charge being constantly in one contactwith respect to each other during the travel of the parts through thefurnace.

It is a well recognized condition that small parts, when otherwiseprogressed through furnaces, are apt to freeze together due to any causesuch as a slight formation of scale bridging from one piece to another.This has existed to such an extent when heat treating small flat pieceswith the flat faces in contact and ushing a mass of such pieces throughthe urnace as to cause such a freezing of pieces as to require aknockoff device at the discharge point, to break up such contact. Therear side of the belt in its return passage is supported by means ofpulleys or drums l3 and 13a, the latter drums being carried on shafts 14and 15, respectively. All the rollers 10, driving drums 12 and 12a anddrums 13 and 13a, are simultaneously driven. Drums l2 and 12a arepreferably so spaced from each other that the catenary 12b of belt 11 issufficient to take up any elongation of the belt, as results from heatexpansion. In some cases I may impart all of the necessary driving powerby means of rollers 10, and in suchcases, therefore, use drums 12, 12a,13 and 13a as idlers.

In order to provide for the coordinated operation of the several drumsand rollers, I provide driving shafts 16 and 17 which are mounted inbearings 18 for rotation in opposite directions by means of bevel gear19 and bevel pinions 20. Power is supplied to the bevel gear 19 throughmain shaft 21 which carries the bevel gear 19. Any suitable source ofpower may be utilized, such as an electric motor with suitable worm orspur gear speed reduction means and variable speed transmission meansbetween the bevel gear 19 and the power source.

The shaft 16 carries a sprocket 22 which drives sprocket member 23 bymeans of chain 24. The sprocket 23 is mounted on the extension of theshaft of one of the horizontally disposed rollers 10. The direction ofrotation of the rollers as governed by'the movement of the sprocket 22is as indicated by the arrows of Fig. 1 of the drawings. All of therollers 10 are interconnected and are driven by means of chains 30 and31 which are looped over sprockets 32 and 33 carried by the extensionson the shafts of adjacent roller members 10. In order to provide forsufficient clearance of each of the looped chains 30 and 31 thesprockets 32 and 33 are offset in different vertical planes, as illustrated in Figs. 2 and 3. j

Shaft 17 carries sprocket 25 driving sprocket 26 by means of chain 25a.Sprocket 26 is carried by the shaft 15 which extends from the drum 130which supports the lower side of the conveyer 11. Shaft 17 also carriessprocket 36 which drives chain 38 to impart movement to sprocket 37which is positioned upon the shaft 14 on which drum 13 is mounted. Thepower for driving the conveyer through the furnace is delivered to drums12 and 12a by means of chains 29 which engage sprockets 27 and 28, andadditional conveying power is imparted to belt by rollers 10 asheretofore described. Sprockets 28 are carried upon the shafts 42 and 43of drum 12 and 12a and are interconnected by the looped chain 29 withthe sprocket 27 on the extension of shafts 10 of the second rollers fromthe end of the set of rollers constituting the conveyer within thefurnace structure.

All of the shafts are journaled in suitable bearings which I haverepresented generally at 44 secured in the steel shell a, or otherwisesuitably mounted.

The diameter of driver and driven sprockets in all cases is such thatthe perimeter speed of rollers 10, drums 12 and 12a and drums 13 and 13aare uniform throughout, thereby transmitting uniform speed ofprogression to belt 11.

Reference character 34; indicates a loading shelf supported on brackets48 on the outside of the furnace, preferably having upturned flanges 35at the side edges of shelf 3-l to guide particles of the charge onto theconveyer belt 11. Material deposited on shelf 34: may be either pushedmanually along shelf 34: onto belt 11 or a pusher mechanism familiar tothose versed in the art may be provided. Furthermore, shelf 3 L may beplaced at an incline, where it would be possible to distribute particlesfrom a conveyer belt onto the incline of shelf 34 and therebyautomatically load parts onto belt 11.

Any suitable means at the discharge end of belt 11 may be provided, asfor example, chute 39, which may discharge by gravity into anyreceptacle, as for example, an oil quench tank shown at 40, andpreferably with discharge end of chute 39 below the level of liquid all.

In the operation of the conveyer system of my invention it will be notedthat sliding friction on the underside of the conveyer belt has beeneliminated, thereby reducing wear upon the belt. It will be noted thatthe conveyer is wholly within the heat treatment chamber of the furnaceand conveyer loss of heat is prevented. By supporting the belt at amultiplicity of intervals by the plurality of rollers 11, distortion ofthe belt beyond the natural catenaries and undulations is prevent ed, sothat an unevenly distributed charge on the belt will not produceundesirable belt tension for elongation of the belt parts. Sliding ofthe conveyer over the hearth of the furnace is prevented by means ofdrums 13 and 13a, and wear upon the conveyer is thereby substantiallyeliminated. By reason of the reduction in tension in the belt a sub- 5stantially lighter weight belt, which is therefore more economical, maybe utilized than in a belt otherwise driven, which must be of sufficientstrength to carry the weight of the entire charge, plus the resultingtension stresses.

I have found the combined belt and roller type of conveyer as describedherein very practical in its construction and successful in itsoperation.

While I have described a preferred embodiment of my invention, I desirethat it be understood that modifications may be made and that nolimitations upon my invention are intended other than are imposed by thescope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of theUnited States is as follows:

1. In a heat treatment furnace of the conveyer type a heat treatmentchamber, an endless belt conveyer mounted for movement wholly withinsaid heat treatment chamber and a plurality of rollers members spaced atintervals along the length of said conveyer and within said chamber forsupporting the under surface of said conveyer and providing means foradvancing charges through said heat treatment chamber during the processof heat treatment, and means for imparting motion simultaneously to saidroller members and to said endless conveyer, discharge means below oneend of said conveyer and a removable door in the end of said chamberabove said discharge means for affording access to the charges on saidconveyer.

2. A heat treatment furnace comprising a heat treatment chamber, anendless conveyer mounted to move wholly within said heat treatmentchamber from the receiving end of said chamber to the discharge endthereof, electric heating elements surrounding said conveyer throughoutthe course of movement thereof, a discharge chute extending from thedischarge end of said conveyer within said chamber to a pointexterior-1y thereof, and a removable door adjacent the discharge end ofsaid chamber and aligned with the plane of the upper portion of saidconveyer, said removable door having electric heating elements thereonfor subjecting charges on said conveyer to heat at the discharge end ofsaid heat treatment chamber.

In testimony whereof I afiix my signature.

WILLIAM B. GOOLEY.

